Optical microscope, stereomicroscope, scanning electronic microscope (SEM) and mechanical property testing were used to research the effects of different quenching temperatures on the microstructure and mechanical p...Optical microscope, stereomicroscope, scanning electronic microscope (SEM) and mechanical property testing were used to research the effects of different quenching temperatures on the microstructure and mechanical properties of the H13 mandrel steel. The results indicate that following an increase in the quenching ,the degree of alloying is enhanced due to the carbides dissolving gradually in austenite, which improves the hardenability of the specimens, as well as their room and high-temperature strength. At the same time, the fracture toughness increases due to the increment of the martensite number and the interparticle distance of impact toughness. Optimal performance Consequently,the service life of the H13 the carbides. However, extremely coarse grain and martensite can decrease the can be obtained after quenching at 1 060℃ and double tempering at 620℃mandrel steel is extended significantly.展开更多
In this study,the microstructural evolution of H13 mandrel steel during its manufacturing process and the influence of the preheat treatment procedure and the second-step tempering temperature on its microstructural a...In this study,the microstructural evolution of H13 mandrel steel during its manufacturing process and the influence of the preheat treatment procedure and the second-step tempering temperature on its microstructural and mechanical properties were investigated.The experiment results showed that,using an H13 mandrel steel billet in the as-annealed condition produced by Baosteel as a raw material,the preheat treatments of normalization,spheroidization annealing,or normalization plus spheroidization annealing,as described in this paper,had no significant effect on the final mechanical properties after quenching and tempering.H13 mandrel steel met all the mechanical property requirements via quenching and tempering without preheat treatment.In the temperature range from 600 to 680 t,with an increase in the second-step tempering temperature,the strength gradually decreased whereas the plasticity and toughness gradually improved.Using the quenching-plus-first-tempering procedure of 1030℃/l h/oil cooling+600℃/5 h/air cooling,good balance between strength and toughness could be achieved by selecting 650℃ as the second-step tempering temperature.The test results also showed that the holding time of the second tempering played a big role in the mechanical properties.When this holding time was extended from 1 to 2 h,the hardness of the H13 mandrel steel decreased and the extent of this reduction increased with an increase in the second-step tempering temperature.In the temperature range of 1030 to 1090℃,the yield strength,tensile strength,and hardness gradually increased,however,the impact toughness decreased with increases in the quenching temperature.展开更多
This study researches the effects of the refining treatment on the microstructure and the mechanical properties of H13 mandrel steel and compares these effects with those of the conventional treatment. The results ind...This study researches the effects of the refining treatment on the microstructure and the mechanical properties of H13 mandrel steel and compares these effects with those of the conventional treatment. The results indicate that both carbide particles and grains were refined, carbide particles were uniformly distributed by the refining treatment, and therefore,the strength and toughness of H13 mandrel steel were improved. Rapid cooling after the solution treatment may inhibit intra-granular precipitation of carbide particles, which is favorable to enhancing toughness. Consequently, high- performance H13 mandrel steel can be produced by proper refining treatment.展开更多
文摘Optical microscope, stereomicroscope, scanning electronic microscope (SEM) and mechanical property testing were used to research the effects of different quenching temperatures on the microstructure and mechanical properties of the H13 mandrel steel. The results indicate that following an increase in the quenching ,the degree of alloying is enhanced due to the carbides dissolving gradually in austenite, which improves the hardenability of the specimens, as well as their room and high-temperature strength. At the same time, the fracture toughness increases due to the increment of the martensite number and the interparticle distance of impact toughness. Optimal performance Consequently,the service life of the H13 the carbides. However, extremely coarse grain and martensite can decrease the can be obtained after quenching at 1 060℃ and double tempering at 620℃mandrel steel is extended significantly.
文摘In this study,the microstructural evolution of H13 mandrel steel during its manufacturing process and the influence of the preheat treatment procedure and the second-step tempering temperature on its microstructural and mechanical properties were investigated.The experiment results showed that,using an H13 mandrel steel billet in the as-annealed condition produced by Baosteel as a raw material,the preheat treatments of normalization,spheroidization annealing,or normalization plus spheroidization annealing,as described in this paper,had no significant effect on the final mechanical properties after quenching and tempering.H13 mandrel steel met all the mechanical property requirements via quenching and tempering without preheat treatment.In the temperature range from 600 to 680 t,with an increase in the second-step tempering temperature,the strength gradually decreased whereas the plasticity and toughness gradually improved.Using the quenching-plus-first-tempering procedure of 1030℃/l h/oil cooling+600℃/5 h/air cooling,good balance between strength and toughness could be achieved by selecting 650℃ as the second-step tempering temperature.The test results also showed that the holding time of the second tempering played a big role in the mechanical properties.When this holding time was extended from 1 to 2 h,the hardness of the H13 mandrel steel decreased and the extent of this reduction increased with an increase in the second-step tempering temperature.In the temperature range of 1030 to 1090℃,the yield strength,tensile strength,and hardness gradually increased,however,the impact toughness decreased with increases in the quenching temperature.
文摘This study researches the effects of the refining treatment on the microstructure and the mechanical properties of H13 mandrel steel and compares these effects with those of the conventional treatment. The results indicate that both carbide particles and grains were refined, carbide particles were uniformly distributed by the refining treatment, and therefore,the strength and toughness of H13 mandrel steel were improved. Rapid cooling after the solution treatment may inhibit intra-granular precipitation of carbide particles, which is favorable to enhancing toughness. Consequently, high- performance H13 mandrel steel can be produced by proper refining treatment.